Investigations designed to use the erythrocyte membrane as a model system with which to study the biochemical defect in Duchenne muscular dystrophy (DMD) are proposed. Previous experiments have demonstrated that DMD erythrocyte membrane band 2 (M.W. approximately 220,000 daltons) can be phosphorylated to a greater extent by (gamma-32 P) ATP. Isolation and characterization of this abormally phosphorylated polypeptide as well as comparisons with human muscle proteins obtained at biopsy are in progress. Current studies involve the use of peptide mapping techniques using high pressure ion exchange liquid chromatography.